I saw once a usage of the macro __unused which is explained here, but for some reason I can't find now where it is defined. Will appreciate help. I need it for an ansi C project. Thanks.
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Elad Weiss
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2It's not an ANSI C macro however. – StoryTeller - Unslander Monica Mar 14 '18 at 13:32
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Also, you might wanna forget about "ANSI C" and instead use ISO C. The C language has been internationally standardized since the year 1990. – Lundin Mar 14 '18 at 13:33
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@Lundin good to know. I thought it just a term for "not c++". – Elad Weiss Mar 14 '18 at 13:40
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3"C" in and of itself implies "not C++". – StoryTeller - Unslander Monica Mar 14 '18 at 13:41
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@StoryTeller Can I define the macro myself? – Elad Weiss Mar 14 '18 at 13:42
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1@EladWeiss - I wouldn't define *that* macro (the two underscore spiel is reserved). But nothing is stopping you from defining your own macro that expands to `__attribute__((unused))`. – StoryTeller - Unslander Monica Mar 14 '18 at 13:43
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@EladWeiss: you can, but you should not. `__` is a reserved prefix. By definining something in it, you should break things. – Giacomo Catenazzi Mar 14 '18 at 13:44
1 Answers
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unused
is GCC specific 6.32.1 Common Variable Attributes
This attribute, attached to a variable, means that the variable is meant to be possibly unused. GCC does not produce a warning for this variable.
NTERNATIONAL STANDARD ©ISO/IEC ISO/IEC 9899:201x does not even mention unused.
sg7
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